Gas-generating agent composition comprising triazine derivative

ABSTRACT

A gas generating composition for an air bag having a low toxicity, a high burning rate and a low combustion temperature is provided.  
     It is a gas generating composition comprising (a) a triazine derivative, (b) a basic metal nitrate, and (c) a binder or (c) a binder and (d) an additive.

FILED OF THE INVENTION

[0001] The present invention relates to a gas generating composition suitable for an air bag restraining system of automobiles and the like, its molded article and an inflator for an air bag using the same.

RELATED ART

[0002] As a gas generating agent for an air bag as a passenger-protecting system in automobiles, a composition using sodium azide has been often used so far. However, a toxicity to human bodies [LD₅₀ (oral-rat)=27 mg/kg] or hazard in handling of sodium azide has been regarded as a serious problem. Therefore, as safe non-azide based gas generating compositions, gas generating compositions containing various nitrogen-containing organic compounds have been developed to replace the above composition.

[0003] For example, U.S. Pat. No. 4,909,549 discloses a composition comprising hydrogen-containing tetrazole or triazole compounds and an oxygen-containing oxidizing agent. U.S. Pat. No. 4,370,181 discloses a gas generating composition comprising a hydrogen-free bitetrazole metal salt and an oxygen-free oxidizing agent. U.S. Pat. No. 4,369,079 discloses a gas generating composition comprising a hydrogen-free bitetrazole metal salt and an alkali metal nitrate, an alkali metal nitrite, an alkaline earth metal nitrate, an alkaline earth metal nitrite or a mixture thereof. U.S. Pat. No. 5,542,999 discloses a gas generating agent comprising a fuel such as GZT, TAGN, NG (nitroguanidine), NTO and the like, a basic copper nitrate, a catalyst for reducing toxic gases and a coolant. JP-A 10-72273 discloses a gas generating agent comprising a bitetrazole metal salt, a bitetrazole ammonium salt or aminotetrazole and ammonium nitrate.

[0004] However, the non-azide based gas generating composition is problematic in combustion temperature, burning rate, phase transfer, amounts of generated carbon monoxide and nitrogen oxides, a gas output and the like. For example, the gas generating composition of U.S. Pat. No. 4,369,079 has a high combustion temperature, and requires a large amount of a coolant in actual use. The composition of U.S. Pat. No. 5,542,999 has a low burning rate, and may not be completely burned in a short time. In the gas generating agent of JP-A 10-72273, a shape of the molded article is changed due to phase transfer of ammonium nitrate in the range of the use temperature, which damages a molded article of the gas generating agent, and in result, stable combustion cannot be conducted. Further, in the related arts on these non-azide based gas generating agents, tetrazoles, nitroguanidine and TAGN are used as the fuel of the gas generating agent. However, these compounds are all hazardous materials, and much care must be taken in view of a safety when handling the same.

DISCLOSURE OF THE INVENTION

[0005] Accordingly, an object of the invention is to provide a gas generating composition which is low in combustion temperature, high in burning rate, reduced in amounts of generated carbon monoxide and nitrogen oxides, good in combustion stability and high in safety at the time of handling, its molded article and an inflator for an air bag using the same.

[0006] The invention provides a gas generating composition comprising (a) a triazine derivative and (b) an oxidizing agent.

[0007] Further, the invention provides a molded article in the form of a single-perforated cylinder, a perforated (porous) cylinder or pellets obtained from the gas generating composition.

[0008] Still further, the invention provides an inflator for an air bag using the gas generating composition and the molded article.

[0009] The gas generating composition and its molded article of the invention are easy to handle because of a low toxicity and less hazard. Moreover, a burning rate is high, a combustion temperature is low, and amounts of generated carbon monoxide and nitrogen oxides are reduced in the combustion.

EMBODIMENTS OF THE INVENTION

[0010] The triazine derivative as component (a) which is used in the invention is preferable because the toxicity is low and in combination with component (b) , the combustion temperature is low and the burning rate is increased.

[0011] As the triazine derivative, at least one selected from triazine (1,2,3-triazine, 1,2,4-triazine or 1,3,5-triazine) melamine, trihydrazinotriazine, trimethylolmelamine, an alkylated methylolmelamine, ammeline, ammelide, ammelande, cyanuric acid, cyanuric acid derivatives such as cyanuric acid esters, melam, melem, melamine nitrate, melamine perchlorate and a nitro compound of melamine such as dinitroammeline is proposed.

[0012] Among these, melamine and trihydrazinotriazine (THT) are preferable because LD₅₀ (oral-rat) is 3,161 mg/kg, the combustion stability is high, the safety is secured in handling and the cost is low.

[0013] With respect to the oxidizing agent as component (b) which is used in the invention, at least one selected from an oxyacid salt, a metal oxide, a metal double oxide, a metal peroxide and a basic metal nitrate is proposed. Among these, a basic metal nitrate is preferable, and a basic copper nitrate is especially preferable.

[0014] The oxyacid salt includes one comprising a cation selected from ammonium, an alkali metal and an alkaline earth metal and a hydrogen-free anion selected from nitric acid, nitrous acid, chloric acid and perchloric acid.

[0015] Examples of such an oxyacid salt include ammonium salts, alkali metal salts and alkaline earth metal salts of nitric acid such as ammonium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate and strontium nitrate; ammonium salts, alkali metal salts and alkaline earth metal salts of nitrous acid such as ammonium nitrite, sodium nitrite, potassium nitrite, magnesium nitrite and strontium nitrite; ammonium salts, alkali metal salts and alkaline earth metal salts of chloric acid such as ammonium chlorate, sodium chlorate, potassium chlorate, magnesium chlorate and barium chlorate; and ammonium salts, alkali metal salts and alkaline earth metal salts of perchloric acid such as ammonium perchlorate, sodium perchlorate, potassium perchlorate, magnesium perchlorate and barium perchlorate.

[0016] The metal oxide, the metal peroxide and the metal double oxide can include oxides, peroxides and double oxides of copper, cobalt, iron, manganese, nickel, zinc, molybdenum and bismuth.

[0017] Examples of the metal oxide, the metal peroxide and the metal double oxide can include CuO, Cu₂O, Co₂O₃, CoO, Co₃O₄, Fe₂O₃, FeO, Fe₃O₄, MnO₂, Mn₂O₃, Mn₃O₄, NiO, ZnO, MoO₃, CoMoO₄, Bi₂MoO₆ and Bi₂O₃.

[0018] The basic metal nitrate includes some compounds represented by the following formula. Further, some compounds include hydrates thereof too. In the formula, M represents a metal, x′ represents the number of metals, y and y′ each represent the number of NO₃ ions, z′ represents the number of OH ions, and n represents a ratio of an M(OH)_(z) moiety to an M(NO₃)_(y) moiety.

M(NO₃)_(y).nM(OH)_(z) or M_(x′)(NO₃)_(y′)(OH)_(z′)

[0019] Examples of the compounds corresponding to the above-described formula include those containing, as a metal M, copper, cobalt, zinc, manganese, iron, molybdenum, bismuth and cerium, such as Cu₂(NO₃)(OH)₃, Cu₃(NO₃)(OH)₅.2H₂O, Co₂(NO₃)(OH)₃, Zn₂(NO₃)(OH)₃, Mn(NO₃)(OH)₂, Fe₄(NO₃)(OH)₁₁.2H₂O, Bi(NO₃)(OH)₂ and Ce(NO₃)₃(OH).3H₂O.

[0020] As the basic metal nitrate, at least one selected from a basic copper nitrate (BCN), a basic cobalt nitrate, a basic zinc nitrate, a basic manganese nitrate, a basic iron nitrate, a basic molybdenum nitrate, a basic bismuth nitrate and abasic cerium nitrate is proposed. Among these, a basic copper nitrate is preferable.

[0021] A basic copper nitrate has, in comparison with ammonium nitrate as an oxidizing agent, an excellent thermal stability because no phase transition occurs in the range of the use temperature and a melting point is high. Further, since a basic copper nitrate acts to decrease a combustion temperature of a gas generating agent, amounts of generated nitrogen oxides can be reduced.

[0022] When the gas generating composition of the invention comprises components (a) and (b), the content of component (a) is preferably 5 to 60 wt. %, more preferably 5 to 50 wt. %, further preferably 10 to 30 wt. %, and the content of component (b) is preferably40 to 95 wt. %, more preferably 50 to 95 wt. %, further preferably 70 to 90 wt. %.

[0023] A preferable example of the composition comprising components (a) and (b) is a composition comprising (a) melamine and (b) a basic copper nitrate. In this case, the content of (a) melamine is 15 to 45 wt. %, preferably 15 to 25 wt. %, and the content of (b) a basic copper nitrate is 55 to 85 wt. %, preferably 75 to 85 wt. %.

[0024] Another preferable example of the composition comprising components (a) and (b) is a composition comprising (a) trihydrazinotriazine and (b) a basic copper nitrate. In this case, the content of (a) trihydrazinotriazine is 15 to 45 wt. %, preferably 15 to 25 wt. %, and the content of (b) a basic copper nitrate is 55 to 85 wt. %, preferably 75 to 85 wt. %.

[0025] The gas generating composition of the invention can further contain a binder as component (c) for increasing a strength of a molded article.

[0026] As the binder, at least one selected from carboxymethylcellulose (CMC), sodium carboxymethylcellulose (CMCNa), potassium carboxymethylcellulose, ammonium carboxymethylcellulose, cellulose acetate, cellulose acetate butyrate (CAB), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), ethylhydroxyethyl cellulose (EHEC), hydroxypropyl cellulose (HPC), carboxymethylethyl cellulose (CMEC), fine crystalline cellulose, polyacrylic amide, amine products of polyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylic amide and a metal salt of acrylic acid, a copolymer of polyacrylic amide and polyacrylic ester compound, polyvinyl alcohol, acrylic rubber, guar gum, starch and silicone is proposed. Among these, sodium carboxymethylcellulose (CMCNa) and guar gum are preferable in consideration of a stickiness, cost and an ignitability.

[0027] The gas generating composition of the invention can further contain an additive as component (d) for reducing amounts of toxic nitrogen oxides and carbon monoxide generated after combustion by decreasing a combustion temperature.

[0028] As the additive, at least one selected from metal oxides such as copper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, bismuth oxide; silica and alumina, metal hydroxides such as aluminum hydroxide, cobalt hydroxide and iron hydroxide, metal carbonates or basic metal carbonates such as cobalt carbonate, calcium carbonate, a basic zinc carbonate and a basic copper carbonate, composite compounds of metal oxides or hydroxides such as Japanese acid clay, kaolin, talc, bentonite, diatomaceous earth and hydrotalcite, metal acid salts such as sodium silicate, mica, molybdate, cobalt molybdate and ammonium molybdate, silicone, molybdenum disulfide, calcium stearate, silicon nitride and silicon carbide is proposed. Among these, aluminum hydroxide and cobalt oxide are preferable.

[0029] One or both of the binder as component (c) and the additive as component (d) can be used.

[0030] When the gas generating composition of the invention comprises components (a) and (b) and (c) and/or (d), the content of component (a) is preferably 5 to 60 wt. %, more preferably 10 to 25 wt. %, the content of component (b) is preferably 40 to 95 wt. %, more preferably 40 to 85 wt. %, further preferably 50 to 80 wt. %, the content of component (c) is preferably 0.1 to 15 wt. %, more preferably 1 to 10 wt. %, and the content of component (d) is preferably 0.1 to 20 wt. %, more preferably 3 to 15 wt. %.

[0031] A preferable example of the composition comprising components (a), (b) and (c) is a composition comprising (a) melamine, (b) a basic copper nitrate and (c) sodium carboxymethylcellulose. In this case, it is preferable that the content of (a) melamine is 15 to 25 wt. %, the content of (b) a basic copper nitrate is 60 to 80 wt. % and the content of (c) sodium carboxymethylcellulose is 0.1 to 10 wt. %.

[0032] Another preferable example of the composition comprising components (a), (b) and (c) is a composition comprising (a) melamine, (b) a basic copper nitrate and (c) guar gum. In this case, it is preferable that the content of (a) melamine is 15 to 25 wt. %, the content of (b) a basic copper nitrate is 60 to 80 wt. % and the content of (c) guar gum is 0.1 to 10 wt. %.

[0033] Other preferable example of the composition comprising components (a), (b) and (c) is a composition comprising (a) trihydrazinotriazine, (b) a basic copper nitrate and (c) guar gum. In this case, it is preferable that the content of (a) trihydrazinotriazine is 15 to 25 wt. %, the content of (b) a basic copper nitrate is 60 to 80 wt. % and the content of (c) guar gum is 0.1 to 10 wt. %.

[0034] A preferable example of the composition comprising components (a), (b), (c) and (d) is a composition comprising (a) melamine, (b) a basic copper nitrate, (c) sodium carboxymethylcellulose and (d) aluminum hydroxide. In this case, it is preferable that the content of (a) melamine is 10 to 25 wt. %, the content of (b) a basic copper nitrate is 60 to 80 wt. %, the content of (c) sodium carboxymethylcellulose is 0.1 to 10 wt. % and the content of (d) aluminum hydroxide is 1 to 15 wt. %.

[0035] Another preferable example of the composition comprising components (a), (b), (c) and (d) is a composition comprising (a) melamine, (b) a basic copper nitrate, (c) sodium carboxymethylcellulose and (d) cobalt oxide. In this case, it is preferable that the content of (a) melamine is 10 to 25 wt. %, the content of (b) a basic copper nitrate is 60 to 80 wt. %, the content of (c) sodium carboxymethylcellulose is 0.1 to 10 wt. % and the content of (d) cobalt oxide is 1 to 10 wt. %.

[0036] Other preferable example of the composition comprising components (a), (b), (c) and (d) is a composition comprising (a) melamine, (b) a basic copper nitrate, (c) guar gum and (d) aluminum hydroxide. In this case, it is preferable that the content of (a) melamine is 10 to 25 wt. %, the content of (b) a basic copper nitrate is 60 to 80 wt. %, the content of (c) guar gum is 0.1 to 10 wt. % and the content of (d) aluminum hydroxide is 1 to 10 wt. %.

[0037] Other preferable example of the composition comprising components (a), (b), (c) and (d) is a composition comprising (a) trihydrazinotriazine, (b) a basic copper nitrate, (c) guar gum and (d) aluminum hydroxide. In this case, it is preferable that the content of (a) trihydrazinotriazine is 10 to 25 wt. %, the content of (b) a basic copper nitrate is 60 to 80 wt. %, the content of (c) guar gum is 0.1 to 10 wt. % and the content of (d) aluminum hydroxide is 1 to 10 wt. %.

[0038] The gas generating composition of the invention can be molded in a desired shape, and formed into a molded article in the shape of a single-perforated cylinder, a perforated (porous) cylinder or pellets. These molded articles can be produced by a method in which the gas generating composition is mixed with water or an organic solvent and the mixture is extrusion-molded (molded articles in the form of a single-perforated cylinder and a perforated (porous) cylinder) or by a compression-molding method using a pelletizer (molded article in the form of pellets).

[0039] The gas generating composition or the molded article obtained therefrom in the invention can be used in, for example, an inflator for an air bag of a driver side, an inflator for an air bag of a passenger side, an inflator for a side air bag, an inflator for an inflatable curtain, an inflator for a knee bolster, an inflator for an inflatable seat belt, an inflator for a tubular system and a gas generator for a pretensioner in various vehicles.

[0040] Further, the inflator using the gas generating composition or the molded article obtained therefrom in the invention may be a pyrotechnic type in which a gas is supplied only from a gas generating agent or a hybrid type in which a gas is supplied from both of a compressed gas such as argon or the like and a gas generating agent.

[0041] Moreover, the gas generating composition or the molded article obtained therefrom in the invention can also be used as an igniting agent called an enhancer (or a booster) for transferring energy of a detonator or a squib to a gas generating agent.

EXAMPLES

[0042] The invention is illustrated more specifically by referring to the following Examples. However, the invention is not limited thereto. In tables, BCN indicates a basic copper nitrate, CMCNa sodium carboxymethylcellulose, Gum guar gum, BHTK potassium bitetrazole and THT trihydrazinotriazine respectively.

Examples 1 to 18 and Comparative Example 1 and 2

[0043] Gas generating compositions each having a formulation shown in Table 1 were produced. A combustion temperature, a gas output (unit “mol/100 g” indicates the number of mols of a generated gas per 100 g of a composition) and amounts of generated CO and NO of these compositions according to theoretical calculations are shown in Table 1. TABLE 1 Combustion Amount of Amount of temperature Gas output generated Co generated NO Formulation (wt. %) (K) (mol/100 g) (mol/100 g) (mol/100 g) Ex. 1 melamine/BCN = 20.8/79.2 1503 2.14 2.5 × 10⁻⁴ 0 Ex. 2 melamine/BCN/CMCNa = 18.8/ 1463 2.16 3.6 × 10⁻² 0 78.2/3 Ex. 3 melamine/BCN/CMCNa = 20.8/ 1358 2.28 0.12 0 76.2/3 Ex. 4 melamine/BCN/Gum = 18.51/7 1449 2.17 3.5 × 10⁻² 0 8.49/3 Ex. 5 melamine/BCN/CMCNa/Al (OH)₃ = 1358 2.15 3.1 × 10⁻² 0 17.76/74.24/3/5 Ex. 6 melamine/BCN/CMCNa/Al (OH)₃ = 1292 2.14 2.8 × 10⁻² 0 16.72/70.28/3/10 Ex. 7 melamine/BCN/CMCNa/Al(OH)₃ = 1177 2.13 2.2 × 10⁻² 0 15.68/66.32/3/15 Ex. 8 melamine/BCN/CMCNa/Co₃O₄ = 1423 2.06 3.5 × 10⁻² 0 17.99/74.01/3/5 Ex. 9 melamine/BCN/CMCNa/Co₃O₄ = 1382 1.97 3.3 × 10⁻² 0 17.18/69.82/3/10 Ex. 10 melamine/BCN/Gum/Al (OH)₃ = 1358 2.16 3.1 × 10⁻² 0 17.47/74.53/3/5 Ex. 11 melamine/BCN/Gum/Al (OH)₃ = 1281 2.15 2.7 × 10⁻² 0 16.43/70.57/3/10 Ex. 12 melamine/BCN/Gum/Al (OH)₃ = 1166 2.14 2.2 × 10⁻² 0 15.39/66.61/3/15 Ex. 13 melamine/BCN/Gum/CO₃O₄ = 1408 2.07 3.4 × 10⁻² 0 17.70/74.30/3/5 Ex. 14 melamine/BCN/Gum/CO₃O₄ = 1367 1.99 3.3 × 10⁻² 0 16.89/70.11/3/10 Ex. 15 THT/BCN = 23.40/76.60 1786 2.28 3.3 × 10⁻³ 7.2 × 10⁻⁵ Ex. 16 THT/BCN/CMCNa = 20.40/76.6 1749 2.24 2.4 × 10⁻³ 2.5 × 10⁻⁵ 0/3 Ex. 17 THT/BCN/Gum = 20.00/77.00/3 1739 2.24 1.2 × 10⁻³ 4.5 × 10⁻⁵ Ex. 18 THT/BCN/Gum/Al (OH)₃ = 18.9/ 1603 2.23 1.8 × 10⁻³ 3.1 × 10⁻⁶ 73.1/3/5 Comp. BHTK/KNO₃ = 51.44/48.56 2393 1.26 5.1 × 10⁻⁴ 4.1 × 10⁻³ Ex. 1 Comp. NaN₃/CuO = 61/39 1421 1.41 0 1.3 × 10⁻⁶ Ex. 2

[0044] The combustion temperatures in Examples 1 to 18 were all lower than that in Comparative Example 1 of the non-azide based gas generating agent by more than 600° C., and the combustion temperatures in Examples 3, 5 to 7 and 9 to 14 were even lower than that in Comparative Example 2 of the azide based gas generating agent. Moreover, in Examples 1 to 14, NO did not occur theoretically, and it was found that an effect of reducing the amount of generated NO was provided in comparison with Comparative Examples 1 and 2. Further, the gas outputs in Examples 1 to 18 were higher than that in Comparative Example 2 of the azide based gas generating agent by more than 50%.

Examples 19 to 24

[0045] Gas generating compositions each having a formulation shown inTable2we reproduced. These compositions were tested for a friction sensitivity and a drop hammer sensitivity according to the explosives performance test method of JIS K 4810-1979. The results are shown in Table 2. TABLE 2 Friction Drop hammer sensitivity sensitivity Formulation (wt. %) (kgf) (cm) Ex. 19 melamine/BCN/CMCNa = 19.80/77.20/3 >36.0 >100 Ex. 20 melamine/BCN/CMCNa/Co₃O₄ = >36.0 >100 17.18/69.82/3/10 Ex. 21 melamine/BCN/CMCNa/Al(OH)₃ = >36.0 >100 16.72/70.28/3/10 Ex. 22 melamine/BCN/CMCNa/Japanese acid >36.0 >100 clay = 20.80/76.20/3/5 Ex. 23 melamine/BCN/CMCNa/SiO₂ = >36.0 >100 20.80/76.20/3/5 Ex. 24 melamine/BCN/CMCNa/mica = >36.0 >100 20.80/76.20/3/5

[0046] In Examples 19 to 24, the friction sensitivity exceeded 36.0 kgf, and the drop hammer sensitivity exceeded 100 cm. Accordingly, it was identified that the safety in handling was high.

Examples 25 to 30

[0047] Gas generating compositions each having a formulation shown in Table 3 were produced. With respect to these compositions, a melting temperature, a temperature at which to start thermal decomposition and a temperature at which to start TGweight loss were measured with a TAS-type differential thermal analyzer manufactured by Rigaku K.K. A rate of temperature rise in the measurement was 20° C./min, a measurement atmosphere was a nitrogen gas, and an amount of a sample in the measurement was 1 to 2 mg. The results are shown in Table 3. TABLE 3 Temperature at which to Temperature Melting start thermal at which to temperature decomposition start weight Formulation (wt. %) (° C.) (° C.) loss (° C.) Ex. 25 melamine/BCN = 25/75 210 237 230 Ex. 26 melamine/BCN/CMCNa = 206 233 214 20.80/76.20/3 Ex. 27 melamine/BCN/CMCNa/Co₃O₄ = 203 229 211 17.18/69.82/3/10 Ex. 28 melamine/BCN/CMCNa/Al(OH)₃ = 204 231 212 16.72/70.28/3/10 Ex. 29 THT/BCN = 23.4/76.6 — 180 185 Ex. 30 THT/BCN/CMCNa = 20.4/76.6/3 — 179 182

[0048] In Examples 25 to 30, it was identified that the melting temperature, the temperature at which to start thermal decomposition and the temperature at which to start weight loss were high enough and the thermal stability was good.

Examples 31 to 35

[0049] Gas generating compositions each having a formulation shown in Table 4 were produced. Each of these compositions was molded into a strand. A burning rate was measured in a nitrogen atmosphere at a pressure of 4,900, 6,860 or 8,820 kPa. A burning rate at 6,860 kPa and a pressure index of 4,900 to 8,820 kPa are shown in Table 4. TABLE 4 Burning rate Pressure Formulation (wt. %) (mm/sec) index Ex. 31 melamine/BCN/CMCNa = 15.89 0.25 19.80/77.20/3 Ex. 32 melamine/BCN/CMCNa/Co₃O₄ = 15.26 0.18 17.99/74.01/3/5 Ex. 33 melamine/BCN/CMCNa/Co₃O₄ = 14.03 0.16 17.18/69.82/3/10 Ex. 34 melamine/BCN/Gum/Al(OH)₃ = 13.98 0.18 17.47/74.53/3/5 Ex. 35 melamine/BCN/Gum/Al(OH)₃ = 10.15 0.20 16.43/70.57/3/10

[0050] The respective values shown in Examples 31 to 35 reveal that the compositions meet the practical conditions as the gas generating composition for the inflator.

Examples 36 to 48

[0051] Gas generating compositions each having a formulation shown in Table 5 were produced. Each of the gas generating compositions was molded into 2 g of a strand. This strand was installed in a closed bomb having an inner capacity of 1 liter, and the inside of the bomb was purged with nitrogen. Further, the bomb was pressurized to 6,860 kPa with nitrogen. The strand was ignited by passage of current through a nichrome wire, and completely burned. Approximately 20 seconds from the passage of current, a combustion gas was collected in a gas sampling bag, and the concentrations of NO₂, NO, CO and CO₂ were immediately analyzed with a detecting tube. TABLE 5 Amount of Amount of Amount of Amount of generated generated generated generated NO₂ NO CO CO₂ Formulation (wt. %) ppm ppm ppm ppm Ex. 36 melamine/BCN = 20.8/79.2 0 37 50 2300 Ex. 37 melamine/BCN/CMCNa = 0 55 110 3000 18.8/78.2/3 Ex. 38 melamine/BCN/CMCNa = 0 42 150 1700 19.8/77.2/3 Ex. 39 melamine/BCN/CMCNa = 0 9 130 1400 20.8/76.2/3 Ex. 40 melamine/BCN/CMCNa/ 0 8 100 1700 Al (OH)₃ = 17.76/74.24/3/5 Ex. 41 melamine/BCN/CMCNa/ 0 13 70 1900 Al (OH)₃ = 15.72/71.28/ 3/10 Ex. 42 melamine/BCN/CMCNa/ Al (OH)₃ = 16.72/70.28/ 3/10 0 6 130 2100 Ex. 43 melamine/BCN/CMCNa/ 0 4 160 1700 Al (OH)₃ = 17.72/69.28/ 3/10 Ex. 44 melamine/BCN/CMCNa/ 0 5 100 1700 Al (OH)₃ = 15.68/66.32/ 3/15 Ex. 45 melamine/BCN/CMCNa/ 0 30 110 1500 Co₃O₄ = 17.99/74.01/3/5 Ex. 46 melamine/BCN/CMCNa/ Co₃O₄ = 17.18/69.82/3/10 0 9 120 1400 Ex. 47 melamine/BCN/CMCNa/ 0 17 170 2100 Japanese acid clay = 20.8/76.2/3/5 Ex. 48 melamine/BCN/CMCNa/ 0 5 220 2100 mica = 20.8/76.2/3/5 

1. A gas generating composition comprising (a) a triazine compound and (b) an oxidant.
 2. The composition as claimed in claim 1, in which (b) the oxidant is an oxygen-containing oxidant.
 3. The composition as claimed in claim 1 or 2, in which (b) the oxidant is at least one selected from the group consisting of an oxyacid-salt, a metal oxide, a metal double oxide, a metal peracid and a basic metal nitrate.
 4. The composition as claimed in claim 3, in which the basic metal nitrate is at least one selected from the group consisting of a basic copper nitrate, a basic cobalt nitrate, a basic zinc nitrate, a basic manganese nitrate, a basic iron nitrate, a basic molybdenum nitrate, a basic bismuth nitrate and a basic cerium nitrate.
 5. The composition as claimed in any one of claims 1 to 4, in which (a) the triazine compound is at least one selected from the group consisting of a triazine compound, a melamine compound, trihydrazinotriazine, trimethylolmelamine, an alkylated methylolmelamine, ammelin, ammelide, ammelande, cyanuric acid, a cyanuric acid compound, melame, melem, melamine nitrate, perchloroacid salt of melamine and nitro melamine.
 6. The composition as claimed in any one of claims 1 to 5, which comprises 5 to 60 wt. % of component (a) and 40-95 wt. % of component (b).
 7. The composition as claimed in any one of claims 1 to 6, which further comprises (c) a binder and/or (d) an additive.
 8. The composition as claimed in claim 7, in which (c) the binder is at least one selected from the group consisting of carboxymethylcellulose, sodium carboxymethylcellulose, potassium carboxymethylcellulose, ammonium carboxymethylcellulose, cellulose acetate, cellulose acetatebutylate, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethylhydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethylethyl cellulose, fine crystalline cellulose, polyarylic amide, amine products of polyacrylic amide, polyacrylic hydrazid, a copolymer of an acrylic amide and a metal salt of acrylic acid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum, starch and silicone.
 9. The composition as claimed in claim 7, in which (d) the additive is at least one selected from the group consisting of metal oxides selected from the group consisting of copper oxide, iron oxide, zinc oxide, cobalt oxide, mangnese oxide, molybdenum oxide, nickel oxide, bismuth oxide, silica and alumina; metal hydroxides selected from the group consisting of aluminum hydroxide, cobalt hydroxide and iron hydroxide; metal carbonates or basic metal carbonates selected from the group consisting of cobalt carbonate, calcium carbonate, a basic zinc carbonate and a basic copper carbonate; composite compounds of metal oxides and metal hydroxides selected from the group consisting of Japanese acid clay, kaolin, talc, bentonite, diatomaceous earth and hydrotalcite, metal acid salts selected from the group consisting of sodium silicate, mica, molybdate, cobalt molybdate and ammonium molybdate, silicones, molybdenum disulfide, calcium stearate, silicon nitrite and silicon carbide.
 10. The composition as claimed in any one of claims 7, 8 and 9, which comprises 0.1 to 15 wt. % of component (c) and 0.1 to 20 wt. % of component (d).
 11. The composition as claimed in any one of claims 1 to 10, in which component (a) is melamine or trihydrozinotriazine and component (b) is a basic copper nitrate.
 12. The composition as claimed in claim 11, which comprises 15 to 45 wt. % of (a) melamine or trihydrozinotriazine and 55 to 85 wt. % of (b) a basic copper nitrate.
 13. The composition as claimed in claim 7, which comprises (a) melamine or trihydrozinotriazine, (b) a basic copper nitrate and (c) sodium carboxymethylcellulose or guar gum.
 14. The composition as claimed in claim 13, which comprises 15 to 25 wt. % of (a) melamine, 60 to 80 wt. % of (b) a basic copper nitrate and 0.1 to 10 wt. % of (c) sodium carboxymethylcellulose or guar gum.
 15. The composition as claimed in claim 13, which comprises 15 to 25 wt. % of (a) trihydrazinotriazine, 60 to 80 wt. % of (b) a basic copper nitrate and 0.1 to 10 wt. % of (c) sodium carboxymethylcellulose or guar gum.
 16. The composition as claimed in claim 10, which comprises 15 to 25 wt. % of (a) melamine, 60 to 80 wt. % of (b) a basic copper nitrate, 0.1 to 10 wt. % of (c) sodium carboxymethylcellulose and 1 to 15 wt. % of (d) aluminum hydroxide or 1 to 10 wt. % of (d) cobalt oxide.
 17. The composition as claimed in claim 10, which comprises 10 to 25 wt. % of (a) trihydrazinotriazine, 60 to 80 wt. % of (b) a basic copper nitrate, 0.1 to 10 wt. % of (c) sodium carboxymethylcellulose and 1 to 15 wt. % of (d) aluminum hydroxide or 1 to 10 wt. % of (d) cobalt oxide.
 18. A molded article of the gas generating composition being in the form of a single perforated cylinder or a perforated cylinder, obtained by extruding the gas generating composition as defined in any one of claims 1 to
 17. 19. A molded article of the gas generating composition being in the form of pellets, obtained by compress-molding the gas generating composition as defined in any one of claims 1 to
 17. 20. An inflator for air bag, using the gas generating composition as defined in any one of claims 1 to 17 or a molded article thereof. 